This invention is generally related to a fluxgate magnetometer for detecting a magnetic field. More particularly, this invention is directed toward a digital magnetometer implemented with a microcontroller.
Non-contact torque sensors utilize a magnetoelastic material applied to a torque transducer. Application of torque to the torque transducer generates a magnetic field. The generated magnetic field is detected and converted to a usable electric signal by a magnetometer. Current magnetometers utilize a fluxgate circuit to detect and convert the generated magnetic field into a usable electric signal proportional to the applied torque.
A fluxgate circuit includes a non-linear magnetic element that is contained within a coil of wire. An alternating electrical current is applied to the coil to generate an alternating magnetic field. The alternating magnetic field magnetically saturates the magnetic element twice each excitation period. An external magnetic field as is generated by the torque transducer is superimposed onto the magnetic field produced by the coil of wire causing an asymmetric saturation of the magnetic element. The asymmetry of the saturation in turn causes a voltage waveform across the coil at a frequency twice that of the excitation frequency. The amplitude and phase of this signal is used as a feedback signal to the coil. The feedback provides a stable, linear sensor response desirable for many sensing applications.
Disadvantageously, conventional fluxgate circuits are comprised of several analog components that require delicate assembly and take up valuable space. Some fluxgate circuits have digitally integrated some features, however, an analog switch is retained for performing heterodyning functions, and also includes an analog buffer device to provide current feedback.
Accordingly, it is desirable to develop and design a magnetometer that does not utilize analog components and that is implemented entirely on an integrated circuit microcontroller.